Rasterization: you trade editability for pixels
A PDF can hold vectors, live fonts, and placed photos. A PNG is a grid of pixels. Convertify4u samples each page at a chosen density and writes a lossless bitmap. After that, text is no longer selectable, hyperlinks are gone, and scaling the PNG further will soften — crop and enlarge in an image tool only if you accept interpolation. Screen-density renders (roughly 72–96 CSS pixels mapped through Edge) are free for everyday files: one PNG for a single page, a ZIP of page_N.png for longer docs. Uploads travel HTTPS; outputs are purged after the session. That is a real upload, unlike Instant Canvas image tools — do not send secrets you are not allowed to process. 300 DPI plus strict alpha is Pro HD on Hetzner because transparent high-DPI pages eat RAM. Long catalogs also belong on VPS so a laptop tab does not die. Common mistake: bursting a 120-page book to PNG and emailing the ZIP uncompressed. Common win: diagrams and UI that JPEG would smear. GIF 256-color palettes are irrelevant here; you are making 24-bit (and optional 32-bit alpha) PNGs, not looping GIFs.
How a convert runs
Drop the PDF, start the job, download PNG or ZIP. No account for eligible standard renders. Heavy OCR, folder queues, and oversized packs route to Pro workers so the tab is not doing CAD-scale rasterization alone.
When PNG is the wrong export
If you still need searchable text, keep the PDF or go to Word/PPT converters. If you need a tiny photo for chat, JPEG from a single page may be smaller. PNG wins for type, screenshots of slides, and alpha.
Related next steps
Compress huge ZIPs before email. Merge if you split first. Image Enlarger only after rasterize, and only when you accept softness. Comparison pages cover Smallpdf, iLovePDF, Convertio, and FreeConvert if you are switching.